1. Field of the Invention
The present invention relates to a three-dimensional imaging system for obtaining a three-dimensional image of an object. In particular, the invention relates to a three-dimensional ultrasound imaging system for obtaining a three-dimensional image of an object scanned using ultrasound scanning techniques disclosed below.
2. Description of the Prior Art
Ultrasound scanning systems of various types are well-known in the prior art. For example, most prior art medical ultrasound scanning systems generally utilized may be classified as A-type or B-type.
In an A-type ultrasound scanner, a fixed transducer provides an ultrasound pulse which is directed along a fixed path into a body or object. The times of return for reflections from internal organic interfaces are detected to provide an indication of the distance to such interfaces.
In a B-type scanner, a pulsed ultrasonic beam is swept in a single direction, and, as in the A-type scanner, the successive distances or ranges to reflecting organic interfaces are determined by standard intervalometer methods. These B-type scanners typically provide an indicia of the interface by, in effect, plotting the detected distances against the position of the beam path. Various B-type scanners have included a real-time display, and have effected scanning electrically, for example, by use of a phased transducer array.
U.S. Pat. No. 4,271,706--Ledley discloses an ultrasonic scanner in which an ultrasonic pulse is directed into a body and electrical representations of pulse reflections from body interfaces, along the path of the ultrasonic pulse, are generated. In the ultrasonic scanner of that patent, the ultrasonic signal path is scanned through a volume of the body, and position signals indicative of the instantaneous position are generated. The reflection signals are selectively gated in accordance with a predetermined function of the path disposition to provide a display selectively representing desired interfaces situated within a selected contoured portion of the volume being scanned. By varying the predetermined function, a specific desired interface surface may be displayed. Provisions for developing a three-dimensional display of the selected surface are described in the aforementioned patent.
Other methods and devices for representing electrical spatial curves and spatial images of electrically reproduced ultrasonic images, X-ray images or cardiac vector loops, as well as an apparatus for collecting three-dimensional data relating to the size, shape, location and nature of soft tissue organ structures, are disclosed in U.S. Pat. No. 4,292,977--Krause et al and U.S. Pat. No. Re. 30,397--King. In addition, an ultrasonic stereoscopic imaging device or apparatus for three-dimensional visualization of an object or substance is disclosed in U.S. Pat. No. 4,028,934--Sollish.
Arrangements involving arrays of transducers, or of ultrasonic transmitters and/or receivers, are disclosed in U.S. Pat. Nos. 3,292,018--Clynes, 3,552,382--Mount, and 3,577,772--Perilhou et al.
The following U.S. patents disclose other ultrasonic systems and devices: U.S. Pat. Nos. 3,681,977--Wendt et al; 3,888,238--Meindl et al; 3,936,791--Kossoff; 3,964,296--Matzuk; 4,075,883--Glover; 4,109,642--Reid et al; and 4,121,468--Glover et al.
The ultrasonic arrangements, devices and systems described in the aforementioned patents are characterized by certain disadvantages. For example, ultrasonic arrangements, devices and systems of the prior art failed to take advantage of theories relating to texture and visual perception, as well as binocular perception. Such theories and the related theoretical techniques are disclosed in the following two articles: "Texture and Visual Perception", by Bela Julesz, Scientific American, February 1965, pages 38-48; and "The Resources of Binocular Perception", by John Ross, Scientific American, March 1976, pages 80-86.
Related to the latter observation is the further observation that ultrasonic arrangements, devices and systems of the prior art failed to take advantage of the advanced state of computer and data processing technology, and specifically failed to take advantage of the savings in hardware which can be achieved by development and adoption of sophisticated data processing/programming techniques for processing ultrasonic system data to derive reconstructed image data for the three-dimensional display of three-dimensional images of objects scanned by the three-dimensional imaging system.